Abstract: Objective: To observe the incidences of cervical abnormalities in patients with different level of deep overbite and the relationship between the craniofacial morphology and the incidences. Methods: The incidences of cervical abnormalities in 124 patients with deep overbite (classified into 3 groups based on different level of deep overbite) and 48 subjects with neutral occlusion were counted, and the lateral cephalometric radiographs were measured and analyzed. Correlation analysis was used to analyze the relationship between cervical abnormalities and measurements. Results: The incidences of normal cervical, fusion anomalies and more than one deviation in the 4 groups were statistically different. There were statistical differences in PP-MP, SN-MP, SNB, ANB, A-N-Pog, ILs-PP, overjet and overbite among the 4 groups. The cervical abnormalities were correlated with PP-MP, ANB, A-N-Pog, ILs-PP, overjet and overbite. Conclusion: The incidences of fusion anomalies and more than one deviation increased with the level of deep overbite. The cervical abnormalities were correlated with mandibular position, vertical jaw relationship, overjet and overbite.

Key words: Deep overbite, Cervical abnormalities, Lateral cephalometric radiograph, Fusion anomalies, Posterior arch deficiency